That varies from region to region. In the UK and the US (I think) they're normally on daily rates, but in other places it's often 10% of the budget (as a guide). Some also have profit share, which means they'll get part of whatever is left after all the production costs and the production co's mark up has been deducted. This is to stimulate the director (and the producer who's often on a similar deal), to come in under budget.

DP's normally have a flat daily rate. That varies with how hot you are on the market, basically. A top notch, award-winning DP like Harris Savides can probably charge somewhere north of $6000 a day.

hummm...
How do you estimate Daily rate?
As a director, he or she has to do and go meeting/perp for location, audition/research/post/presentation/etc
And Someone told me some directors don't get paid 10% even Highly budgeted project.

I know these are guild rates, but they establish a pretty decent norm, especially for the budget you're talking about.

They do have a low budget commercial rate that wasn't posted:

Special provisions apply to low budget commercials whose total costs do not exceed $75,000 for a one-day shoot, or $150,000 for a two-day shoot or $225,000 for a three-day shoot. No single day?s costs may exceed $75,000.

Not sure the current IATSE rates for DPs on a commercial, but from 10/1/2005 it was $84.59/hr or $676.75 for 8 hours (within LA County). I'd expect that it may have gone a up a little since then, but it's a good ballpark.

On the plus side, I think you may be allowed to abuse your director a little longer than 8 hours before you need to pay OT.